One of the most important art works produced in late fifteenth-century Spain is the group of twenty-six panels from the altarpiece of the cathedral of Ciudad Rodrigo, Castile. The panels rank among the most beautiful and iconographically ambitious works by two of Castile's great late medieval painters, Fernando Gallego and the virtually unknown Master Bartolome. All twenty-six panels are part of the Samuel H. Kress Collection and were given to the University of Arizona Museum of Art in Tuscon in 1957.This major publication sheds new light on the altarpiece and its context, and includes essays on the physical life of the altarpiece itself; Fernando Gallego and the Hispano-Flemish tradition in Spain; Master Bartolome and millennialism in late fifteenth-century Castile; the infra-red reflectography, pigment and medium analysis of the panels; and the role of prints in the altarpiece. These essays together highlight the individual techniques and workshop practices within the context of the cosmopolitan communities of gothic Castile. Full catalogue entries for each of the panels complete the work.The project represents a groundbreaking international collaboration between institutions and scholars headed by the Meadows Museum in close collaboration with the University of Arizona Museum of Art, the Getty Research Institute and the Kimbell Art Museum, whose conservation studio oversaw the technical analysis of the panels.